Irregular surfaces on articular cartilage in the joints of mammals are considered defects known to compromise the function of such joints. When possible, arthroscopic surgery is the preferred method for remediating such defects. Presently, there exist several arthroscopic devices for the treatment of such articular cartilage defects. These devices can generally be divided into three categories. The first category includes bipolar heating devices such as a bipolar wand produced, for example, by Arthrocare. The second category includes laser devices. The third category includes radio frequency devices produced, for example, by Mitek and Oratec.
All of these prior art devices effect the application of heat to the surface-to-be-treated, in response to which the collagen fiber bundles that make up articular cartilage at or near the surface "melt", or soften, and become moldable. Articular cartilage that has been melted or softened by application of heat is referenced to hereinafter as "softened". The depth of the penetration of heat, however, has a negative effect on the cartilage consequences. It is preferred that the heat penetration is minimized in order to prevent damage to the underlying bone. In fact, laser devices have been virtually abandoned for treatment of articular cartilage defects because the laser energy often penetrates the bone, sometimes resulting in osteonecrosis. Invariably, all the prior art devices have the additional drawback of having tips with elevated temperatures, which often burn the surrounding tissue. This burning can leave a charred residue in the joint which can later cause complications in the joint after the surgery. Thus, a need remains for a device and method for treating articular cartilage defects which would have relatively little heat penetration and would not burn the surrounding tissue in the mammalian joint.